I'm definitely curious about your Arduino Master & Processing code. I'm attempting to implement better control of my coat from a computer and wonder how you handled the bandwidth for that :-) I don't know if having an intermediary chip will be ideal, but I definitely am curious.

"I've been working on a LED coffee table , with 112 RGB led's underneath a frosted glass top. This is accomplished by multiplexing the common cathode leds. the red green and blue colors are on for roughly 2ms a piece, much faster than the human eye can perceive so it appears a solid color."

It will walk you through all the basics, including some sample code. Once you go through that, if you have more questions, you should start a new thread in the Hardware Interfacing Section. If you search around you will also find some good info.